How to build a small deck for timber cubby house?

[PatDIY_Dad]

Hey 

I am going to build a deck that will be about 200mm off ground level and will be 2.5m x 2.5m

I have a few questions

I want to concrete some hardwood fence posts as the stumps

How deep in the ground should they go in?

I will put in 9 stumps. I will buy minimum quantity of sand and rock mix for concrete from the local nursery 

How many bags of cement would be needed for 9 holes?

Then I will fix 3 long treated pine joists to the stumps. What size would be suitable?

I will do something similar to this video https://youtu.be/QTQeIZT4U-I

[Jewelleryrescue]

Hi @PatDIY_Dad 

That video showed them digging holes approximatly 500mm below ground  height asa  guide if you look at there  auger is has tape lines as depth guages so they go to the same level every time each hole.  A suitable  depth for purpose.

The trick  here is to dig small diameter holes so the timbers go in and less concrete is needed. Larger (deeeper or wider)  the  holes the more concrete needed.

Look at in vesting/borrowing in a small auger, or a post hole shovel for this   task it will help keep hole size smaller.

ps  As a  must do  use H4 treated  pine for this type of footing.

I dont recommend  buying sand and gravel  from the nursery for smaller  jobs  unless you are also doing more  concretng  later on. A nursery will charge  $70 to 80 delivery fee but will deliver sandand  gravel in the same load.

As  for concreting the best  easiest option is to buy premixed   sand and cement bags at bunnings  All you have to do is  use a  wheel barrow is  easiest and mix in water and it is ready to go,  

Some people use a fast set cement for this that sets fast in near 15mins I highly recommend  you dont buy this for your first rodeo as regular sand cement slower  setting allows you more time to position things  correctly if some thing needs fixing.

For a  500mm hole you  will need 2 to 3 bags of sand and cement 20 KG per hole If you have bags  left over get a  refund on the unopened ones

You  want  9  Stumps  so  thats  27 bags. Probably buy 20 bags initailly and see how you go if  bunning quite close to you.

Australian Builders 20kg Sand And Cement Mix Bag I/N: 0760612  $10^.07

https://www.bunnings.com.au/australian-builders-20kg-sand-and-cement-mix-bag_p0760612

[PatDIY_Dad]

Thanks for the info 

I'll see if anyone has a auger I can borrow 

A 1/4 meter of mixed crush rock and sand is $30 from my local store 

It will end up costing me more if I buy pre-mixed bags

I have already some pieces of hardwood fence posts I just hope they are long enough for the job 

[Jewelleryrescue]

Hi @PatDIY_Dad 

I agree with you if you can get  the 1/4 metre cheaper and you  can do this and mix it with cement powder it will be alot cheaper  as a Guide you will need 4 to 5 bags of  general purpose cement powder.  You can return un opened bags to bunnings for refunds.

I personally am at the cross roads of a mini cement project is it  cheaper to order some sand and  gravel  or  buy the pre mix  bags. lol

I usually have a 5 tonne pile  at a  time I just start mixing.

[EricL]

Hello @PatDIY_Dad  

Thanks for sharing your question about building a deck for your cubby house. I strongly suggest having a quick look at these guides How to build a low-level deck by @Adam_W and How to build a deck. by @MitchellmcMc. These guides will give you an idea of what to take into consideration when planning your decking frame.

Here is a link to ideas and inspiration: Top 10 most popular deck projects

I also suggest having a look at the Bunnings deck building video guide:  

• How to plan out your deck
   
• How to set out a deck
   
• How to install stumps
   
• How to install bearers
   
• How to install joists
   
• How to lay decking
   
• How to add a step to your deck.

I propose drawing your decking frame on paper first before you begin digging holes for the stumps. Once you've finalized the plan on paper share it with the community along with any questions you might have.

If you need further assistance, please let us know.

Eric

[PatDIY_Dad]

Thanks 

We did the footings today

$30 for 1/4 meter of sand and rock mix

used 3 bags of cement $21  

for 9 footings ( not that deep we did about 300mm deep ) I am guessing if you did a proper deck for adults and entertainment you would need to go deeper

Now would anyone here have advice on how to do a picture frame style deck boards? I want to know if you start the border picture frame first or do you do that last and after you put all the main boards on ?

Picture frame deck like this picture:

[EricL]

Hello @PatDIY_Dad 

I suggest having a look at this discussion - Picture frame decking frame dimensions? by @Alan__. Mitchell gives a great explanation about picture framing.  

If you need further assistance, please let us know.

Eric